Controlled unloading of geometrically ordered packed beds



June 4, 1968 H. SUSSKIND ETAL 3,386,527

CONTROLLED UNLOADING OF GEOMETRICALLY ORDERED PACKED BEDS Original FiledApril 22, 1966 2 Sheets-Sheet 2 INVENTORS.

HERBERT sussxmo By WALTER w. BECKER MlCHAEL w. MARESCA,

DECEASED, BY

MARIE MARESCA,ADMINISTRATRIX United States Patent "ice 3,386,627CONTROLLED UN LOADIN G OF GEOMETRICALLY ORDERED PACKED BEDS HerbertSusskind, Huntington, and Walter W. Becker, Shoreham, N.Y., and MichaelW. Maresca, deceased, late of East Patchogue, N.Y., by Marie Maresca,administratrix, East Patchogue, N.Y., assignors to the United States ofAmerica as represented by the United States Atomic Energy Commission.

Original application Apr. 22, 1966, Ser. No. 545,803, now Patent No.3,294,645, dated Dec. 27, 1966. Divided and this application July 22,1966, Ser. No. 578,902

Ciaims. (Cl. 222-193) ABSTRACT OF THE DISCLOSURE An arrangement for theremoval of spherical elements from a container assembled into an orderedpacked bed. Nozzles direct liquid into the container above the bed tofluidize the upper portion of the bed and carry the elements away. Asflow through the nozzles is increased additional layers from the bed areremoved.

This is a division of application Ser. No. 545,803 filed on Apr. 22,1966, now Patent No. 3,294,645, for Controlled Unloading ofGeometrically Ordered Packed Beds.

The invention described herein was made in the course of, or under acontract with the U.S. Atomic Energy Commission.

The present invention concerns the unloading of ordered packed beds andmore particularly the use of hydraulic techniques for the controlled andselective unloading of ordered packed beds of spheres.

In the fast nuclear reactor covered in U.S. Patent 3,335,061 issued Aug.8, 1967 in the names of Warren E. Winsche and Melvin M. Levine, entitledCountercurrent Breeder Reactor, the fuel is shufiled within the core atregular intervals to maintain a predetermined relationship of fertilematerial, fissile material and reactivity at any given instant andlocation in the core. A fuel arrangement which is capable of such use inthe aforementioned reactor consists of ordered packed bed assemblies ofspherical fuel elements or balls as described in U.S. Patent 3,262,859entitled Ordered Bed Nuclear Fuel Assemblies issued July 26, 19-66 inthe name of Warren E. Winsche. Removal of the fuel elements from thecontainers can be accomplished by opening the floor supporting the bedof elements in the container so that the elements can be permitted toflow out under the influence of gravity.

The nuclear reactor described in the aforementioned CountercurrentBreeder Reactor requires the progessive movement of fuel from theextremities of the core towards the central region as the plutoniumconcentration builds up in the fuel. In the course of the operating lifeof the reactor this means that the fuel elements would be movedregularly and perhaps frequently. Under these conditions, mechanicalhandling of the fuel balls would be slow, inefficient and complex. Inaddition, there is the problem of removing heat and fission productsfrom the fuel balls while outside of the reactor or in transit.

In order to avoid these difficulties and other problems which would beencountered by the mechanical handling of large numbers of sphericalfuel elements, this invention provides a completely different approachutilizing hydraulic handling of the elements instead of purelymechanical means. In accordance with this invention, the fuel balls areintroduced into the packed bed by way of a liquid carrier, are removedby selective fiuidization of 3,386,627 Patented June 4, 1968 theuppermost layers of the balls, and are collected and classified forstorage and use or re-use in the fuel containers are elsewhere.Hydraulic handling of the fuel balls can be carried out either directlyinside the reactor vessel or in an external hot cell. In either case,this invention has the advantage of providing for more rapid and safehandling of the fuel as well as affording greater flexibility andefficiencies than heretofore obtainable. Furthermore, the liquid carrierprovides a convenient mechanism for removing heat and fission productswhile the fuel balls are being handled and stored.

It is thus a first object of this invention to provide improved handlingof the fuel in an ordered packed bed nuclear reactor.

It is another object of the invention to provide for the improvedhandling of the spherical particles in any ordered packed bed.

Another object is a hydraulic arrangement for the unloading of orderedpacked beds of spherical particles.

Other objects and advantages of this invention will hereinafter becomereadily apparent from the following description of preferred embodimentsof this invention taken with reference to the accompanying drawings inwhich:

FIG. 1 is an elevation view in section of a column containing sphericalelements and embodying the principles of this invention;

FIG. 2 is a View along 2--2 of the column illustrated in FIG. 1;

' FIG. 3 is a schematic view of the interior of colum FIG. 1 showingfluid flow; and

FIG. 4 is an assembly for the controlled unloading of a complete columnand classification storage of the removed spherical elements.

Referring to FIGS. 1 and 2 there is shown a vertical column 10 which isrectangular in cross-section and contains a bed 11 of sphericalparticles 12 supported by a perforated plate 14 as described in thepreviously mentioned U.S. patent application Ser. No. 457,536 toestablish the ordered packed bed as therein described. Column 10, whichmay be a fuel assembly for a nuclear reactor, consists of a pair ofoppositely facing walls 16 and 18, upper and lower end pieces or caps 22and 24, and upper and lower nozzles 26 and 28 for permitting flow offluids therethrough. Upper and lower caps 22 and 24 are provided withopenings 10a and 1%, respectively, to permit communication between theinterior of column 10 and upper and lower nozzles 26 and 28,respectively.

Located at the same elevation or a short distance above the upper levelof bed 11 are a pair of rectangular nozzles 32 and 34 in walls 16 and18, respectively, of column 10. Nozzles 32 and 34 extend upwardly in aninwardly direction, as illustrated, and extend along the entire width oftheir respective walls, as shown in FIG. 2. A pair of manifolds 36 and38 located outside column 10 completely enclosed the outside entrancesto nozzles 32 and 34, respectively. Manifold tubes 42 and 44 providecommunication into manifolds 36 and 38, respectively. Valves V and V inmanifolds 42 and 44 respectively, permit fluid flow to be varied asdesired.

In the operation of the apparatus described, it is desired to removeparticles 12 within column 10 in such a way that after removal it ispossible to arrange them according to their vertical position in column10. A liquid which may be the coolant in the reactor or any othersuitable liquid such as water is supplied under pressure to column 10 byway of tubes 42 and 44, manifolds 36 38, and nozzles 32 and 34. Ascolumn 10 becomes filled with the liquid, a form of turbulence to belater described will be generated within column 10 above bed 11 due tothe manner in which the liquid is jetted into the interior 3 of column10. As the pressure is increased within manifolds 35 and 38 the velocityof the liquid jets through nozzles 32 and 34 will be increased.Eventually it will be found that the first layer of particles will befluidized and carried away by the liquid leaving column 10 through exitnozzle 26. By increasing the pressure of the liquid further the nextlayer will become fluidized and carried away. In this way, by graduallyincreasing the pressure of the liquid supplied to mainfold 10 it ispossible selectively and sequentially to remove predictably and in anorderly fashion the particles within column 16. An additional advantageof this invention when embodied into a nuclear reactor is that theliquid can be used simultaneously as a means for carrying away heat offission and fission products while the particles are in transit andstored.

A detailed study of the mechanism which causes this phenomenon to occurhas been made and it appears that nozzles 32 and 34 set up a pair ofside-by-side vortices within column 10 as a result of a transfer ofmomentum, and each vortex sets up a cooperating vortex directly beneathit, much as schematically illustrated in FIG. 3. Thus it has been foundthat the angle of nozzles 32 and 34 is very important. The smaller angleA is from vertical the more effective and eflicient are the results.That is, the smaller angle A is,'the less fluid velocity is required toreach down a given depth to pick off a particular layer of particles.Further, the velocities of the liquid emerging from nozzles 32 and 34must be equal to each other in order to obtain uniform removal ofparticles.

In the arrangement of FIGS. 1 and 2, it was pointed out that byincreasing the pressure of liquid supplied to nozzles 32. and 34 it isfeasible to remove a whole bed, or a portion of a bed, one layer at atime. As it is readily apparent from the discussion of FIG. 3, thegreater the distance the turbulent fluid acts through, the more dampingtakes place and somewhat less efficient the operation becomes. Referringto FIG. 4 there is illustrated a column 50 in which several sidemanifolds 52a, 52b, 52c and 52d are provided, each leading to nozzles(not shown) in the side walls of column 59. Each of the side manifoldsis provided with a valve 54a, 54b, 54c, and 54d, respectively, which maybe operated either manually or automatically in sequence. A pump Psupplies water or other liquid to the manifolds while the upper end ofcolumn 50 opens into a classifier 58 having a series of traps 62a, 62b,62c, and 62d. Each of the traps 6261-6261 is provided with an opening atthe bottom controlled by a valve 64a, 64b, 64c and 64d, respectively,leading to a manifold 66 sloped to return the particles to column 50 orto any other receptacle as desired (not shown). Thus, assuming column 50to be filled with a packed bed of spherical particles and it is desiredto remove these particles in the manner previously described, valve 54ain manifold 52a would be open and all the others closed. When the upperportion of the bed is removed, valve 54a would be closed and valve 54bopened. While this sequence takes place the pressure of the liquid iscycled in any known fashion to remove sequentially a series of particlelayers for each valve opening as described earlier. Thus, the bed ofparticles in column 50 can be efficiently and effectively removed.Classifier 58 which receives the fluidized particles is designed tosegregate the particles by position in column 50. Hence, the uppermostlayers of the particles in column 50 will fill trap 62a and the nextlayers will fill trap 6212, etc. When column 50 is emptied of theparticles and all of traps 62a-6Zd are filled, the particles can bereturned to column 50 or delivered elsewhere in any rearrangementdesired by the order in which traps 62a-62d are emptied through thecontrol of valves 64a-64d. This arrangement for returning the particlesis of course illustrative only as it may not be desired to return theparticles to column 50.

It is thus seen that there has been provided a unique way to effect thecontrolled and selective unloading of an ordered packed bed of sphericalparticles by the use of hydraulics. While only preferred embodiments ofthe invention have been shown and described it is understood that manyvariations thereof may be made without departing from the principles ofthis invention. Hence the invention is not to be limited by theparticular examples described but is to be defined only by the scope ofthe appended claims.

What is claimed is:

1. Apparatus for the controlled and selective unloading of a bed ofspherical particles comprising container means for establishing saidbed, and controllable means for fluidizing and carrying away only aselected portion of said bed, the latter said means including at leastone nozzle for injecting liquid into said container means through theside thereof at a point above the level of said bed in a direction abovethe horizontal.

2. The apparatus of claim 1 in which said controllable means includesmeans to vary the velocity of said liquid entering said container toeffect selective removal of said particles.

3. The apparatus of claim 2, in which said controllable means includes asecond nozzle oppositely facing the first nozzle, said nozzles beinglocated on opposite sides of said container means for injecting liquidinto said container.

4. The apparatus of claim 3 in which the velocities of the liquidleaving said nozzles are substantially the same.

5. An assembly comprising a vertically extending column containing anordinarily stationary ordered bed of spherical particles, at least onenozzle extending inwardly and upwardly through a side wall of saidcolumn above said bed of particles, and means for varying the flow ofliquid supplied under pressure through said nozzle to fluidizeselectively portions of said bed to permit the removal of said particlesfrom said column in a predictable and orderly manner.

References Cited UNITED STATES PATENTS 1,949,354 2/1934 Burnside 2091582,728,632 12/1955 Matheson 209157 X 2,946,439 7/1960 Condolios et al209157 SAMUEL F. COLEMAN, Primary Examiner.

